Comment on 'Magnetic skyrmions in atomic thin Crl_3 monolayer; [Appl. Phys. Lett. 114,232402 (2019)]

摘要

Recently, Behera et al. reported the existence of magnetic skyrmions in the monolayer of CrI_3~1 In their theoretical study, the authors claimed that a skyrmionic ground state was spontaneously formed in the presence of an out-of-plane external electric field (E_(Field)) and in the absence of the external magnetic field at T=0K. This skyrmionic state was induced at E_(field)= 0.2 V/A by a strong Dzyaloshinskii-Moriya interaction (DMI) with respect to magnetic anisotropy energy (MAE), both of which the authors calculated using density-functional theory (DFT). In this comment, we show that the claim of Behera et al. concerning the existence of the skyrmionic ground state at 0.2-V/A E_(field) is incorrect and based on a drastically overestimated DMI value by more than one order of magnitude. Our DMI values are also a result of a similar-level-of-accuracy DFT method, and they completely eliminate the possibility of a skyrmionic ground state at the given electric field. This occurs due to the dominance of the exchange and anisotropy terms with respect to the DMI term, which is bound to lead to a collin-ear arrangement of spins as the authors of Ref. 1 explain.